1. Field of the Invention
The present invention relates generally to cassettes, and more particularly to a light-tight cassette for handling and dispensing a roll of photosensitive web material, such as phototypesetting paper and film.
2. Description of the Prior Art
Cassettes for holding and dispensing a roll of light-sensitive photosensitive web material, such as phototypesetting paper and film, are well known in the art. Such cassettes are in the form of a rectanguloid box-like casing comprising four side walls formed from a single sheet of material in which the ends thereof define a pair of faceted tubes. When the cassette is erected, a narrow web exit passageway is defined by two opposed facets of the respective tubes. A pair of end closure caps close the side edges of the side walls, and further have central hub portions for rotatably supporting the roll within the cassette. At least one of the detachable end caps of such known cassettes has spaced inner and outer peripheral wall portions defining a peripheral channel for receiving the side edges of the side walls.
A problem with such known cassettes is that the exit passageway thereof does not have a substantially constant gap width extending from one of the side edges of the side walls of the cassette to the opposite side edges. This is particularly a problem with cassettes designed to handle and dispense web materials of a width in excess of 12 inches. In such cassettes, the gap width in the portion of the passageway intermediate the side edges of the side walls is enlarged, resulting in possible light leakage in that portion of the passageway, and in unequal pressure being exerted on the exiting web material from one side edge of the web to the opposite side edge thereof.
Accordingly, an object of the present invention is to provide a light-tight cassette in which this problem of uneven gap width and unequal pressure disbursement on the web material from one side edge thereof to the opposite side edge is overcome, thereby resulting in a cassette of equal pressure disbursement on the exiting web material and improved light integrity.